Project GRAD is a Demonstration and Education project designed to evaluate an intervention that promotes regular physical activity in college students as they make the transition to post-graduation lifestyles. The proposed intervention targets long-term change in documented determinants of physical activity, is based on contemporary models of behavior change, and is deliverable at moderate cost. College seniors were chosen as the target population because intervention and follow-up are readily generalized through academic courses and alumni associations to the 13 million college students in 3,500 institutions of higher education in the U.S. While it is recognized that high school students who do not attend college are at higher risk, the infrastructure is lacking in high schools for long-term, generalizable interventions. Physical inactivity is now recognized as a major behavioral risk factor for premature mortality and cardiovascular disease. Though the benefits of physical activity are well known, at least 30-40% of U.S. adults have sedentary lifestyles. It is clear that physical activity declines with age throughout the lifespan, and young adulthood may be a critical period. If the Year 2000 Objectives for physical activity are to be attained, interventions are needed to prevent the decline with age. Project GRAD will recruit 424 subjects from a randomly selected pool of seniors from a large multi-ethnic state university. Students will be randomly assigned to intervention and control conditions. The intervention is based on theory as well as pilot research. A pre- graduation course for free credit includes a weekly lecture on exercise science and behavior change principles. Two lab sections each week, led by peer health educators, teach physical activity skills and foster implementation of behavioral skills. There are separate labs to promote adoption or maintenance of physical activity. The course will prepare students to be active after graduation. The 18-month post-graduation intervention will be delivery by low-cost phone counseling by peer health educators and behaviorally-oriented, print information. Instructional videotapes will be available for loan, and free or discount memberships at health clubs will be obtained for subjects. Control subjects will also receive a free course on general health issue, but it will not focus on physical activity or behavioral change methods. Physical activity and selected mediating variables will be assessed annually for two years after baseline. The primary outcome measure will be the 7-day physical activity recall, which has been previously validated in several populations. The validity of the measure will be monitored in substudies throughout the grant period. A secondary aim is to predict physical activity in this young adult population using social support, self-efficacy, perceived barriers, baseline fitness, baseline skinfold measures, and demographics variables. The team of investigators is experienced in all aspect of the proposed study: project management, study design, measurement, application of behavioral theories, intervention development, subject recruitment, cohort maintenance, student health service, data management and analysis, and scientific report writing. The investigators have worked together on various projects previously. We hypothesize that students who receive the intervention will be more active during follow-up than students who do not receive the intervention. Revised intervention materials will be developed ready for dissemination.